1. Field of the Invention
The present invention relates to an apparatus for teaching principles of mechanics and more particularly to an apparatus that can be mechanically propelled and perform experiments related to principles of motion.
2. Background Art
Academic courses covering basic principles of physics, such as mechanics and dynamics, may use teaching aids or hands-on experiments to supplement textual materials. Prior teaching aids or devices consisted of fixed position equipment that could be configured to perform a particular experiment. For example, an apparatus for teaching principles of kinetic and potential energy may consist of rolling a ball down a stationary inclined track and making appropriate measurements and observations. Such teaching aids or devices cannot be easily adapted to perform multiple or different types of experiments. As a result, additional equipment must be purchased to perform different experiments. Such purchases may be cost prohibitive in an educational setting, especially when many devices must be procured to provide students with adequate access and/or time to conduct experiments. In addition to being cost prohibitive, using different equipment for each experiment inhibits students from drawing inferences and analogies that become apparent when a single device is reconfigured to perform multiple experiments.
Before applicant""s invention, there was a need for an apparatus or system for assisting in teaching principles of mechanics and for an apparatus or system that could be cost-effectively reconfigured to perform multiple experiments. Problems associated with the prior art as noted above and other problems are addressed by the applicant""s invention as summarized below.
According to one aspect of the present invention, a mechanically propelled apparatus for teaching principles of mechanics is provided. The apparatus includes a drive wheel supported by a frame and rotatable about a first axis of rotation and a power drum supported by the frame and rotatable about a second axis of rotation. The drive wheel has a peripheral surface for rolling in contact with a support surface and a relatively smaller cylindrical drive surface. At least one flexible tensile member transmits energy from a weight to the drive wheel via the power drum. Movement of the weight causes the power drum and the drive wheel to turn, thereby propelling the apparatus.
A support member may be pivotably connected to a platform and configured to support the power drum. The support member may pivot between vertical and horizontal positions and may be secured in an intermediate position between the vertical and horizontal positions. The support member may include an aperture for receiving a pin that engages the power drum and prevents the power drum from rotating about the first axis of rotation. The first axis of rotation may be parallel to and/or positioned below the second axis of rotation.
The power drum may include first and second portions disposed concentric to the second axis of rotation. The first portion may have a larger or smaller diameter than the second portion.
The drive wheel may include a wheel portion, a drive spool portion, and a flange having a slot and/or an aperture. The aperture may be configured to receive a pin for manually turning the drive wheel. The drive spool portion may have a smaller diameter than the wheel portion.
A first flexible tensile member may be connected to the power drum at a first end and wrapped around the drive spool portion at a second end. The second end may include a ball portion. The slot in the drive wheel may be configured to receive the ball portion when the first flexible tensile member is wound around the spool portion and release the ball portion when the first flexible tensile member is unwound from the spool portion. The first flexible tensile member may be unwound from the drive spool portion and wound around the power drum when the power drum is turned. The first flexible tensile member may engage the first portion of the power drum having a larger diameter than the second portion to decrease torque at the drive wheel. The first flexible tensile member may also engage a second portion having a smaller diameter than the first portion to decrease rotational velocity of the drive wheel.
A second flexible tensile member may be connected to the weight at a first end and wound around the first or second portion of the power drum at a second end.
A line catcher may be configured to secure the second end of the first flexible tensile member when the second end is spaced apart from the drive wheel. The line catcher may be configured to stop the first flexible tensile member from winding around the power drum after the first flexible tensile member is disengaged from the drive wheel.
According to another aspect of the invention, a mechanically propelled vehicle for conducting mechanics experiments is provided. The vehicle includes first and second wheels rotatably attached to a chassis. A support member is pivotably coupled to the chassis and selectively moveable between an upright position and a horizontal position. A power drum is rotatably attached to the support member. A first flexible tensile member is selectively coupled to the power drum and configured to turn the first wheel when the power drum is rotated. A second flexible tensile member is attached to the power drum at a first end and attached to a weight at a second end. When the weight is released from a raised position above the chassis, the power drum rotates and winds the first flexible tensile member around the power drum and unwinds the first flexible tensile member from the first wheel to propel the vehicle.
According to another aspect of the present invention, an apparatus for teaching principles of mechanics and performing experiments is provided. The apparatus includes a power drum rotatable about a first axis of rotation and having first and second spool portions. A drive wheel is rotatably attached to the apparatus along a second axis of rotation and includes wheel and drive spool portions. A first flexible tensile member for transmitting force to the drive wheel is configured to be wound around either the first spool portion or the second spool portion. A second flexible tensile member is attached to the weight and is configured to be wound around the first or second spool portion that is not engaged by the first flexible tensile member. The first flexible tensile member unwinds from the drive wheel and the second flexible tensile member unwinds from the power drum as the weight falls from an elevated position. The first flexible tensile member may be disengaged from the drive spool portion when force is not being transmitted to the drive wheel.
The apparatus may include an arm assembly having an arm member and a wheel. The arm member may be pivotal about the first axis of rotation. The wheel may be disposed on a third axis of rotation and configured to support the arm member when the arm member is disposed in a substantially horizontal deployed position. The arm member may be pivotable between a stored position where the arm member contacts the chassis and the deployed position. The arm member may also be disposed in a substantially vertical jack position to raise the drive wheel. A data acquisition device, such as a transducer, may be attached to the arm member to detect movement of the wheel. Alternately, the data acquisition device may be attached to the apparatus.